Rest API Link Issue comments cannot be set to internal

Hi, I am setting two issues to be linked via the rest api (platform). It allows the addition of a comment for the outward linked item. I am using a simple paragraph/text structure from the comment clock.

When I use the EntityProperty on the comment block with “key”:“sd.public.comment” and value set to “internal”:true, then post to the rest/api/3/issueLink/ resource, the comment is posted as public, not internal.

e.g.

{
    "type": {
    "name": "Duplicate"
  },
   "inwardIssue": {
     "key": "XXX-9002"
   },
   "outwardIssue": {
     "key": "XXX-9001"
   },
   "comment": {
     "body": {
       "version": 1,
       "type": "doc",
       "content": [
         {
           "type": "paragraph",
           "content": [
             {
               "type": "text",
               "text": "Database detected this was a duplicate of PPG-9001 Comment1"
             }
           ]
         },
         {
           "type": "paragraph",
           "content": [
             {
               "type": "text",
               "text": "Private Comment2"
             }
           ]
         }
       ]
     },
     "properties": [
       {
         "key": "sd.public.comment",
         "value": {
           "internal": true
         }
       }
     ]
   }
 }

If I use the exact same comment json with that same entity property using the rest/api/3/issue/{key}/comment resource, then the comment is correctly marked as internal.

Is it expected behaviour for the issueLink post to ignore the internal setting?

Many thanks,
Mark.